dextrorotatory dex·tro·ro·ta·to·ry (děk'strə-rō'tə-tôr'ē) or dex·tro·ro·ta·ry (-rō'tə-rē)adj. Turning or rotating the plane of polarization of light to the right or clockwise, as for solutions or isomers, usually designated as d- in chemical names.